Make it more flexible to use latest version. Make nexus user own the process.

[i11]

1. Fetch latest version
2. Define version and release dynamically
3. Make nexus user own files and processes
4. Patch init.d script to avoid proper shell requirement.

[jbraeuer]

Thanks for your pull request. It might however take some time until I can have a look... Thanks for your patience. J

[jlgrock]

Yeah, you need to pull that request. That's two years, lol. Thanks for the updates though guys, it helped me with an installation problem I ran into with securing the user.